We report combined experimental and theoretical studies of dipotassium terephthalate as anode material for K-ion battery application. Both pristine and carbon nanotube-containing dipotassium terephthalate materials are synthesized using an ultrafast microwave-assisted method. We found that carbon nanotube (CNT)-containing dipotassium terephthalate composite electrode delivers an initial reversible capacity of 247 mAh/g with 78% capacity retention, whereas pristine K₂Tp deliveries an initial reversible capacity of 212 mAh/g with 53% capacity retention at the end of 100 cycles, at a current density of 50 mA/g. The density functional theory-based calculations have shown superior stability of dipotassium terephthalate lattice against the intercalation of potassium atoms. The quantum calculations are also employed to unravel the specifics of intercalation energetics of potassium ions into dipotassium terephthalate lattice. The intercalation and de-intercalation potentials of K-ions are obtained using cyclic voltammetry and compared with theoretical calculations under the assumption of a two-electron transfer reaction. The results of this study lay the ground for understanding the electrochemical processes involved in the operation of an organic anode in K-ion batteries, and thereby can facilitate the design of optimal organic molecular crystal-based electrode materials for battery applications.

我们报告结合对苯二甲酸二钾作为K离子电池应用负极材料的实验和理论研究。使用超快微波辅助方法合成了原始的和含碳纳米管的对苯二甲酸二钾材料。我们发现，包含碳纳米管（CNT）的对苯二甲酸二钾复合电极的初始可逆容量为247 mAh / g，容量保留率为78％，而原始K ₂Tp的初始可逆容量为212 mAh / g，在100次循环结束时的容量密度为53％，电流密度为50 mA / g。基于密度泛函理论的计算表明，对苯二甲酸二钾晶格对钾原子的嵌入具有出色的稳定性。量子计算还可以用来阐明将钾离子嵌入对苯二甲酸二钾晶格中的嵌入能的细节。使用循环伏安法获得K离子的嵌入和脱嵌电势，并在两电子转移反应的假设下将其与理论计算进行比较。这项研究的结果为理解K离子电池中有机阳极的运行所涉及的电化学过程奠定了基础，